Which monosaccharide is the monomer that forms glycogen and starch?

• A. Ribose
• B. Fructose
• C. Glucose
• D. Galactose

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the question by identifying the key terms. The problem is asking for the specific monosaccharide (a simple sugar) that serves as the building block (monomer) for glycogen and starch, which are polysaccharides.
2. Step 2: Recall the structure and function of glycogen and starch. Glycogen is the storage form of carbohydrates in animals, while starch is the storage form in plants. Both are composed of repeating units of a specific monosaccharide linked together.
3. Step 3: Review the properties of the monosaccharides listed in the options: Ribose, Fructose, Glucose, and Galactose. Ribose is a pentose sugar found in RNA, Fructose is a hexose sugar found in fruits, Galactose is a hexose sugar found in lactose, and Glucose is a hexose sugar that serves as a primary energy source in cells.
4. Step 4: Connect the biological role of glucose to the formation of glycogen and starch. Glucose is the monosaccharide that polymerizes to form glycogen in animals and starch in plants through glycosidic bonds.
5. Step 5: Conclude that glucose is the correct answer based on its role as the monomer for glycogen and starch, and its widespread importance in energy storage and metabolism.